Utilities transfer system in a lithography system

ABSTRACT

Techniques for transferring utilities to and from a reticle or wafer stage in a lithography system while minimizing physical disturbances that affect the stage are described. These techniques involve transferring utilities to and from the stage without making physical contact with the stage. Alternatively, utilities are transferred by making physical contact with the stage while the stage is in a stationary position. In addition to transferring utilities to and from the stage, devices such as processing devices, buffers (storage mediums), electrical components, and mechanical components can be placed within the stage to use and/or control the transferred utilities.

RELATED APPLICATION DATA

This application is a continuation application of U.S. application Ser.No. 10/734,396, filed Dec. 12, 2003, by Alton Hugh Phillips andentitled, “Utilities Transfer System In A Lithography System”, nowpending, the content of which is hereby incorporated by reference hereinfor all purposes.

FIELD OF THE INVENTION

The present invention relates generally to lithography systems, and morespecifically to techniques for minimizing physical disturbances andcontamination of wafer or reticle stages when transferring utilities tosuch stages.

BACKGROUND OF THE INVENTION

Lithography systems are used to manufacture semiconductor devices byexposing semiconductor wafers to specific patterns of light. This istypically done by shining light, through a patterned reticle, onto thewafers. A reticle is supported within a reticle stage, which is in turnsupported by a frame. The reticle stage is supported in a way that itcan be precisely moved with respect to the frame and thereby withrespect to the wafer. The reticle stage can be supported throughmechanical devices such as actuators or through resistance-freetechniques that employ air pressure or electromagnetic forces. In somelithography systems, a wafer stage, which supports a wafer, can also beprecisely moved with respect to a supporting frame.

The reticle or wafer stages require one or more utilities, such aselectrical power, electrical control signals, fluids (e.g., for coolingpurposes), and gases (e.g., to function as a conductor) to function.Such utilities are usually transferred to and from a stage throughflexible cables and hoses. Usually, the utilities are transferredbetween the stage and the supporting frame. Unfortunately, typicalproblems with such transfer techniques include vibration transmissionbetween the stage and the frame, particle generation by the connectinghoses and cables, and leaks by the hoses and cables. Vibrationtransmission occurs because the cables and hoses provide a vibrationpath between the stage and the frame. This causes a reduction in stagepositioning performance. Also, cables and hoses can be caused to vibrateif a natural mode of the cables and hoses is excited either by the stagemotion or by the base motion. Particle generation is problematic becausemoving cables and hoses can generate particles as they bend, flex, andrub on fixed surfaces. These particles can reduce performance oflithographic processes if they should migrate to the reticle, optics,wafer, or metrology devices. Finally, leakage is always a risk sinceflexible hoses can break.

The solutions to reduce risk of such problems have led to stiff, bulky,or high bend-radius cables and hoses, which consume space or worsenvibration transmission. Other solutions to reduce these risks includelimiting coolant material to one, which is less effective than water,but evaporates quickly and is non-corrosive to system components.

These problems are especially problematic with Next GenerationLithography (NGL) systems, which require extremely high tolerances. Onetype of NGL system is an Extreme Ultraviolet (EUV) system, whichoperates in a vacuum and utilizes specially coated mirror optics.Reticles in EUV systems are supported on one side of a chuck, which isattached to the reticle stage, so that light from the light source canbe reflected off of the reticle. In addition to the already discussedproblems, EUV systems have additional problems that are associated withflexible cables and hoses. For one, out gassing of water andhydrocarbons from the flexible hoses can have adverse affects on thelife of optical elements. For example, water can corrode opticalelements and such damage is irreparable. Also, hydrocarbons reduceoptical reflectivity over time, which will reduce system throughput. Outgassing also adversely affects the time to reach operating vacuumlevels. The possible solution of baking-out cables and hoses only makesthem stiffer which in turn exacerbates certain problems.

In view of the foregoing, techniques for transferring utilities to areticle or wafer stage without accompanying physical disturbances orcontaminating particles or gases would be desirable.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to techniques for transferringutilities to and from a reticle or wafer stage in a lithography systemwhile minimizing physical disturbances that affect the stage. Thesetechniques involve transferring utilities to and from the stage withoutmaking physical contact with the stage. Alternatively, utilities aretransferred by making physical contact with the stage while the stage isin a stationary position.

One aspect of the invention pertains to a lithography system having atransformer, a stage, and a frame. The transformer includes an inductivecore, a primary inductive coil, and a secondary inductive coil, whereinthe inductive core has a first and a second end and wherein the primaryinductive coil is wrapped around the first end of the inductive core.The stage is suitable for supporting a wafer or a reticle wherein thestage houses the secondary inductive coil, and the frame supports thestage and the inductive core such that the second end of the inductivecore extends into the secondary inductive coil, wherein each sidesurface of the inductive core maintains a minimum distance of separationfrom an inner surface of the secondary inductive coil, wherebyelectrical power supplied to the primary inductive coil can be drawn bythe secondary inductive coil.

Another aspect of the invention pertains to a lithography system havinga stage suitable for supporting a wafer or a reticle, a frame thatsupports the stage, a stage utility transfer means for transferringutilities between the stage and the frame, the stage utility transfermeans being located within or on a surface of the stage, and a frameutility transfer means for transferring utilities between the stage andthe frame, the frame utility transfer means being located within or on asurface of the frame, whereby the stage and the frame can remainphysically separated from each other while utilities are transferredbetween the stage and the frame.

Another aspect of the invention pertains to a method for transferringutilities between a stage and a base of a lithography system. The methodincludes connecting a supply channel between the frame and the stage,transferring utilities between the stage and the frame through theconnected supply channel, and disconnecting the supply channel from thestage. A particular implementation of the method further includesstabilizing the stage from a scanning motion to a stationary positionbefore connecting the supply channel, and then causing the stage toresume a scanning motion after disconnecting the supply channel.

Another aspect of the invention pertains to a lithography system havinga transformer that includes at least a primary inductive coil, asecondary inductive coil, a stage, and a frame. The secondary inductivecoil has a first end and a second end wherein the first and second endsare at opposite ends of a lengthwise axis of the secondary inductivecoil. The stage is suitable for supporting a wafer or a reticle whereinthe stage is attached to at least the first end of the secondary coiland thereby supports the secondary inductive coil. The frame supportsthe primary coil such that the primary coil is proximate to thesecondary coil wherein the primary coil and the secondary coil maintaina separation distance from each other when the stage moves relative tothe frame along the lengthwise axis of the secondary coil. An electricalcurrent within the primary coil creates an electromagnetic field thatcauses electrical current to flow within the secondary inductive coil.

Yet another aspect of the invention pertains to a lithography systemhaving a stage suitable for supporting a reticle or wafer, a stage portlocated on a surface of the stage, a frame for supporting the stage, aframe port located on a surface of the frame wherein the stage port andthe frame port are suitable for making a connection with each other sothat gas and/or fluids can be transferred between the stage and theframe, and a frame vacuum pump within the frame, the frame vacuum pumphaving vacuum passageways that extend to the surface of the frame atpositions around a perimeter of the frame port, whereby the frame vacuumpump can evacuate any gas and/or fluids that leak from the connectionbetween the stage port and the frame port.

These and other features and advantages of the present invention will bepresented in more detail in the following specification of the inventionand the accompanying figures, which illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further advantages thereof, may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 illustrates an overview of the common components of a lithographysystem.

FIG. 2 illustrates a perspective, cross-sectional view of a reticlestage, its supporting frame, and the devices for non-contact transfer ofutilities according to one embodiment of the present invention.

FIG. 3 illustrates a side, cross-sectional view of the stage of FIG. 2along line 3-3.

FIG. 4A illustrates a perspective view of a frame and a stage thatutilize an alternative embodiment of a transformer for non-contacttransfer of electrical power between the frame and the stage.

FIG. 4B illustrates a top-plan view of the frame and the stage of FIG.4A.

FIG. 5A illustrates a perspective view of a frame and a stage thatutilize yet another alternative embodiment of a transformer fornon-contact transfer of electrical power between the frame and thestage.

FIG. 5B illustrates a top-plan view of the frame and the stage of FIG.5A.

FIG. 6 illustrates an enlarged, cross-sectional view of a stage and aframe where non-contact transfer of gas and fluids can occur.

FIG. 7 illustrates a side, cross-sectional view of a stage and a framethat transfers utilities through contact techniques according to oneembodiment of the present invention.

FIG. 8 illustrates an enlarged view of the interface between a stage anda frame according to an alternative embodiment of the invention whereinports make contact with each other in order to transfer gases and/orfluids.

FIG. 9 illustrates an exemplary process for fabricating semiconductordevices using the systems described above.

FIG. 10 illustrates a detailed flowchart example of the above-mentionedstep 1004 of the process of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference toa few preferred embodiments as illustrated in the accompanying drawings.In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art, that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known operations have not beendescribed in detail so not to unnecessarily obscure the presentinvention.

The present invention pertains to techniques for transferring utilitiesto and from a stage in a lithography system while minimizing physicaldisturbances that affect the stage. The stages are those that support areticle or a semiconductor wafer. These techniques allow the hightolerances for positioning the stage with respect to critical componentsof the lithography system to be satisfied. The techniques also satisfythe stringent requirements for maintaining a contaminant-free processingenvironment. These techniques involve transferring utilities to and fromthe stage without making physical contact with the stage. Alternatively,utilities are transferred by making physical contact with the stagewhile the stage is in a stationary position. In addition to transferringutilities to and from the stage, devices such as processing devices,buffers (storage mediums), electrical components, and mechanicalcomponents can be placed within the stage to use and/or control thetransferred utilities.

FIG. 1 illustrates an overview of the common components of a lithographysystem 100. The following section describes these components; howevernote that the pertinent components of system 100 relative to the presentinvention are reticle stage 116, reticle 118, and optical frame 112.Reticle stage 116, which supports reticle 118, is supported by and movesin controlled motions with respect to optical frame 112. As reticlestage 116 moves, light from above or below reticle 118 can be used toilluminate a specific pattern upon selected areas of wafer 124. Thedevices relating to the transfer of utilities between stage 116 andoptical frame 112 will be described in detail following the descriptionof these common components. Note that although reticle stage 116 isshown to be positioned above optical frame 112, other lithographysystems position the reticle stage within a supporting frame (see FIGS.2 and 5).

Although the present discussion will focus on utilities transfer betweenreticle stage 116 and optical frame 112, the concepts of the presentinvention apply equally to utilities transfer between a wafer stage andits supporting structure. For example, the utilities transfer techniquesof the present invention can be implemented upon wafer stage 122 andlower enclosure 126. The concepts relating to buffering and processingdevices within reticle stage 116 also can be implemented within waferstage 122.

Lithography system 100 includes a mounting base 102, a support frame104, a base frame 106, a measurement system 108, a control system (notshown), an illumination system 110, an optical frame 112, an opticaldevice 114, a reticle stage 116 for retaining a reticle 118, an upperenclosure 120 surrounding reticle stage 116, a wafer stage 122 forretaining a semiconductor wafer 124, and a lower enclosure 126surrounding wafer stage 122.

Support frame 104 typically supports base frame 106 above mounting base102 through a base vibration isolation system 128. Base frame 106 inturn supports, through an optical vibration isolation system 130,optical frame 112, measurement system 108, reticle stage 116, upperenclosure 120, optical device 114, wafer stage 122, and lower enclosure126 above base frame 106. Optical frame 112 in turn supports opticaldevice 114, reticle stage 116, and reticle 118 above base frame 106through optical vibration isolation system 130. As a result thereof,optical frame 112 and its supported components and base frame 106 areeffectively attached in series through base vibration isolation system128 and optical vibration isolation system 130 to mounting base 102.Vibration isolation systems 128 and 130 are designed to damp and isolatevibrations between components of lithography system 100. Any of thepreviously describe seals 132 are placed between base frame 106 (theupper enclosure 120) and the lens assembly 114. The described sealingarrangement provides a good seal for the enclosure 120, yet helpsprevent the transmission of vibrations between the enclosure and thelens assembly 114. Measurement system 108 monitors the positions ofstages 116 and 122 relative to a reference such as optical device 114and outputs position data to the control system.

Optical device 114 typically includes a lens assembly that projectsand/or focuses the light or beam from an illumination system 110 thatpasses through reticle 118. In other embodiments of apparatus 100,illumination system 110 and optical device 114 is set up to projectand/or focus light such that it reflects off of reticle 118.

Reticle stage 116 is set upon optical frame 112 so that reticle stage116 can move through controlled movements (e.g., scanning motions) withrespect to optical frame 112 and wafer 124. Reticle stage 116 can be setupon guides that help guide the movement of reticle stage 116. Or,reticle stage 116 could be a guideless type stage that uses no guides.Exemplary guides include air bearings, ball bearings, electromagneticbearings (Lorentz force, Maxwell force), or permanent magnets. Reticlestage 116 can be moved in the desired motions by movers. Movers can bevarious types of actuators such as piezoelectric actuators,electromagnetic actuators (Lorentz force, Maxwell force), pneumaticactuators, and ball and screw actuators among others.

Similarly, wafer stage 122 can be set upon lower enclosure 126 andguided through controlled movements with or without guides as describedfom reticle stage 116. Also wafer stage 122 can be moved with similarmovers as described for reticle stage 116.

When magnetic levitation is used, reticle stage 116 could be driven byan electromagnetic planar motor. Such a motor could have a magnet unitwith two-dimensionally arranged magnets and an armature coil unit havingtwo-dimensionally arranged coils in facing positions. With this type ofdriving system, either one of the magnet unit or the armature coil unitis connected to the stage and the other unit is mounted on the movingplane side of the stage.

Movement of reticle stage 116 and wafer stage 122 as described abovegenerates reaction forces, which can affect performance of thephotolithography system. Reaction forces generated by wafer (substrate)stage 122 motion can be mechanically released to the floor (ground) byuse of a frame member as described in U.S. Pat. No. 5,528,118 andpublished Japanese Patent Application Disclosure No. 8-166475.Additionally, reaction forces generated by reticle (mask) stage 116motion can be mechanically released to the floor (ground) by use of aframe member as described in U.S. Pat. No. 5,874,820 and publishedJapanese Patent Application Disclosure No. 8-330224. The disclosures inU.S. Pat. Nos. 5,528,118 and 5,874,820 and Japanese Patent ApplicationDisclosure No. 8-330224 are incorporated herein by reference.

As will be appreciated by those skilled in the art, there are a numberof different types of photolithographic devices. For example,lithography system 100 can be used as a scanning type photolithographysystem, which exposes the pattern from reticle 118 onto wafer 124 withreticle 118 and wafer 124 moving synchronously. In a scanning typelithographic device, reticle 118 is moved perpendicular to an opticalaxis of lens assembly 114 by reticle stage 116 and wafer 124 is movedperpendicular to an optical axis of lens assembly 114 by wafer stage122. Scanning of reticle 118 and wafer 124 occurs while reticle 118 andwafer 124 are moving synchronously.

Alternately, lithography system 100 can be a step-and-repeat typephotolithography system that exposes reticle 118 while reticle 118 andwafer 124 are stationary. In the step and repeat process, wafer 124 isin a constant position relative to reticle 118 and lens assembly 114during the exposure of an individual field. Subsequently, betweenconsecutive exposure steps, wafer 124 is consecutively moved by waferstage 122 perpendicular to the optical axis of lens assembly 114 so thatthe next field of semiconductor wafer 124 is brought into positionrelative to lens assembly 114 and reticle 118 for exposure, Followingthis process, the images on reticle 118 are sequentially exposed ontothe fields of wafer 124 so that the next field of semiconductor wafer124 is brought into position relative to lens assembly 114 and reticle118.

However, the use of lithography system 100 provided herein is notlimited to a photolithography system for a semiconductor manufacturing.Lithography system 100, for example, can be used as an LCDphotolithography system that exposes a liquid crystal display devicepattern onto a rectangular glass plate or a photolithography system formanufacturing a thin film magnetic head. Further, the present inventioncan also be applied to a proximity photolithography system that exposesa mask pattern by closely locating a mask and a substrate without theuse of a lens assembly. Additionally, the present invention providedherein can be used in other devices; including other semiconductorprocessing equipment, machine tools, metal cutting machines, andinspection machines.

The illumination source (of illumination system 110) can be g-line (436nm), i-line (365 nm), KrF excimer laser (248 nm), ArF excimer laser (193nm) and F₂ laser (157 nm). Alternatively, the illumination source canalso use charged particle beams such as x-ray and electron beam. Forinstance, in the case where an electron beam is used, thermionicemission type lanthanum hexaboride (LaB₆,) or tantalum (Ta) can be usedas an electron gun. Furthermore, in the case where an electron beam isused, the structure could be such that either a mask is used or apattern can be directly formed on a substrate without the use of a mask.

With respect to lens assembly 114, when far ultra-violet rays such asthe excimer laser are used, glass materials such as quartz and fluoritethat transmit far ultra-violet rays is preferably used. When the F₂ typelaser or x-ray is used, lens assembly 114 should preferably be eithercatadioptric or refractive (a reticle should also preferably be areflective type), and when an electron beam is used, electron opticsshould preferably comprise electron lenses and deflectors. The opticalpath for the electron beams should be in a vacuum.

Also, with an exposure device that employs vacuum ultra-violet radiation(VUV) of wavelength 200 nm or lower, use of the catadioptric typeoptical system can be considered. Examples of the catadioptric type ofoptical system include the disclosure Japan Patent ApplicationDisclosure No. 8-171054 published in the Official Gazette for Laid-OpenPatent Applications and its counterpart U.S. Pat. No. 5,668,672, as wellas Japan Patent Application Disclosure No. 10-20195 and its counterpartU.S. Pat. No. 5,835,275. In these cases, the reflecting optical devicecan be a catadioptric optical system incorporating a beam splitter andconcave mirror. Japan Patent Application Disclosure No. 8-334695published in the Official Gazette for Laid-Open Patent Applications andits counterpart U.S. Pat. No. 5,689,377 as well as Japan PatentApplication Disclosure No. 10-3039 also use a reflecting-refracting typeof optical system incorporating a concave mirror, etc., but without abeam splitter, and can also be employed with this invention. Thedisclosures in the above mentioned U.S. patents, as well as the Japanpatent applications published in the Official Gazette for Laid-OpenPatent Applications are incorporated herein by reference.

The present invention can also be implemented when lithography system100 is an extreme ultraviolet lithography (EUVL) system. In EUVLsystems, illumination source 110 generates light at extremely smallwavelengths. For example, light of wavelengths in the range ofapproximately 13 nm that is produced by laser produced plasma (LPP) orgas discharged plasma (GDP) can be used. Optical components of EUVLsystems typically use reflective optics with special multilayer coatingsof silicon and molybdenum since refractive optics absorb an excessiveamount of the EUV radiation. Also, since most gases absorb EUVradiation, the EUV beam path is typically contained within a vacuumenvironment.

As described above, a photolithography system according to theabove-described embodiments can be built by assembling varioussubsystems, including each element listed in the appended claims, insuch a manner that prescribed mechanical accuracy, electrical accuracyand optical accuracy are maintained. In order to maintain the variousaccuracies, prior to and following assembly, every optical system isadjusted to achieve its optical accuracy. Similarly, every mechanicalsystem and every electrical system are adjusted to achieve theirrespective mechanical and electrical accuracies. The process ofassembling each subsystem into a photolithography system includesmechanical interfaces, electrical circuit wiring connections and airpressure plumbing connections between each subsystem. Needless to say,there is also a process where each subsystem is assembled prior toassembling a photolithography system from the various subsystems. Once aphotolithography system is assembled using the various subsystems, totaladjustment is performed to make sure that every accuracy is maintainedin the complete photolithography system. Additionally, it is desirableto manufacture an exposure system in a clean room where the temperatureand humidity are controlled.

Now that the common components of a lithography system have beendescribed, FIGS. 2, 3, 4A and 4B, 5A and 5B, and 6 will describe thetechniques for transferring utilities that do not require physicalcontact between a stage and its supporting structure or any type ofutility supply device. These techniques are referred to as thenon-contact techniques for transferring utilities. Then FIGS. 7 and 8will describe the techniques that involve physical contact between astage and its supporting structure or any type of utility supply device,referred to as the contact techniques.

FIG. 2 illustrates a perspective, cross-sectional view of a reticlestage 200, its supporting frame 202, and the devices for non-contacttransfer of utilities according to one embodiment of the presentinvention. The rest of the components of a lithography system are notrepresented in FIG. 2 to more clearly represent the aspects of thepresent invention. FIG. 3 illustrates a side, cross-sectional view ofstage 200 of FIG. 2 along line 3-3. Non-contact utilities transferrefers to utilities transfer where there is substantially zero stiffnessbetween stage 200 and frame 202 and the transfer devices applysubstantially zero net force on the stage (i.e. applies no disturbingnet force to the stage). Such transfer can occur while stage 200 ismoving with respect to frame 202, for example while stage 200 isscanning. The utilities can also be transferred while stage 200 isstationary, for example in between wafer processing steps.

The cross-section of frame 202 of FIG. 2 is taken approximately at amid-point such that one-half of frame 202 is shown. The cross-section ofstage 200 is taken near one end of stage 200. In assembled form stage200 would freely slide into slot 204 and be completely enclosed by frame202. Stage 200 is similar to a picture that is set within a pictureframe. As discussed earlier, techniques using electromagnets or airpressure can be used to suspend and control the movement of stage 200within slot 204 of frame 202. Stage 200 supports a reticle 206, which isaccessible to a light source through opening 208 of frame 202. FIG. 3shows electronics compartments 220 that provide room for buffer devices,processing devices, sensors, and other types of devices.

FIG. 2 is meant to show the typical structure of stage 200 and frame 202and to serve as a backdrop for describing the techniques fortransferring utilities between the two structures. Therefore, it shouldbe understood that the transfer techniques of the present invention canalso be implemented in stages and frames having different configurationsand methods of use. For example, stage 200 can support a reticle 206that is meant to transmit light or reflect light onto a semiconductorwafer. The embodiment shown in FIGS. 2 and 3 is suitable for light toreflect off of reticle 206 where reticle 206 is supported with aseparate support structure referred to as a chuck 207. Such a chuck 207,as shown in FIG. 3, can be independently oriented with respect to stage200 through the use of actuators, drivers, sensors, etc.

One of the utilities that needs to be delivered to stage 200 iselectrical power. A transformer is one non-contact device used totransfer power through electrical induction. A transformer 210 is shownin FIG. 2 to extend into frame 202, within slot 204, and along theoutside surface of frame 202. Transformer 210 includes an inductive core212, an inductive primary coil 214, and a inductive secondary coil 216.Primary coil 214 is wrapped around the portion of inductive core 212that is outside of stage 200 and frame 202. Secondary coil 216 is housedwithin stage 200. As is commonly understood, a current through primarycoil 214 creates an electromagnetic field that is directed by inductivecore 212 so that the electromagnetic field causes current to flow withinsecondary coil 216. In other words, power is supplied to primary coil214 so that inductive secondary coil 216 can draw power throughinductive core 212. Inductive secondary coil 216 is secured within stage200 such that the portion of inductive core 212 within slot 204 insertsinto inductive secondary coil 216 when stage 200 is inserted into slot204. The portion of inductive core 212 within slot 204 is positioned sothat inductive secondary coil 216 can freely move over inductive core212 while stage 200 moves along a scanning axis 218 during scanningprocesses. To ensure contact-free, relative motion between inductivecore 212 and secondary coil 216, the inner diameter of secondary coil216 should be larger than the largest diameter of inductive core 212. Asshown in FIG. 2, the longitudinal axis of the portion of inductive core212 within slot 204 is substantially parallel to the longitudinal axisof secondary coil 216.

The configuration of transformer 210 allows power to be drawn fromsecondary coil 216 without any physical contact between secondary coil216 and inductive core 212. Physical contact between stage 200 and frame202 is also avoided when stage 200 is supported through air levitationor electromagnetic levitation techniques. With non-contact stagelevitation and power transmission techniques, power can be supplied to amoving or stationary stage 200 while minimizing physical disturbanceforces to stage 200. Additionally, contaminants from power cables thatcould be used to supply power to stage 200 are also avoided.

In alternative embodiments, multiple inductive secondary coils can bearranged to loop over inductive core 212 within stage 200. By havingmore than one inductive secondary coil, stage 200 can draw power atdifferent voltage levels from each of the inductive secondary coils. Inyet other embodiments, multiple transformers can be positioned atvarious locations of stage 200 and frame 202. Accordingly, stage 200would have multiple inductive secondary coils to receive an end of theinductive core for each of the transformers. For example, a transformercan be placed on each side of stage 200. Smaller transformers can beused in this manner so that power at different voltages can be drawnfrom each transformer.

FIG. 4A illustrates a perspective view of a frame 400 and a stage 402that utilize an alternative embodiment of a transformer for non-contacttransfer of electrical power between frame 400 and stage 402. FIG. 4Billustrates a top-plan view of frame 400 and stage 402 of FIG. 4A. Notethat only the portion of frame 400 that is necessary to describe the useof the transformer is illustrated in FIGS. 4A and 4B. This embodiment ofthe transformer includes an inductive core 404 that is built into frame400, an inductive primary coil 406, and an inductive secondary coil 408.Frame 400 has two openings 410 that are separated by inductive core 404.Primary coil 406 is wrapped around inductive core 404. Secondary coil408 is looped such that it has a larger diameter and encompassesinductive core 404 and primary coil 406. Secondary coil 408 is supportedat its ends by stage 402. Secondary coil 408 also passes through each ofopenings 410 of frame 400 in close proximity to primary coil 406.Secondary coil 408 does not make contact with primary coil 406 or core404 so that stage 402 and secondary coil 408 can freely move withrespect to frame 400 during a scanning motion of stage 402. Stage 402can move back and forth along scanning axis 412 such that thelongitudinal axis of secondary coil 408 passes through openings 410. Thelength of secondary coil 408 can be adjusted depending upon the lengthof the stroke desired for the transformer.

In an alternative embodiment, the transformer can function without acore. In other words, a primary and a secondary coil will more relativeto each other without the presence of a core. For example, primary coil406 could be suspended within frame 400 that does not have an inductivecore 404. Coreless inductive power transfer devices can also be used,however such devices tend to be less efficient than transformers usingiron cores and there is a higher risk of generating disturbance forces.

The configuration of the transformer of FIGS. 4A and 4B can also beimplemented in an opposite fashion as shown. In other words, in analternative embodiment, what is described above as frame 400 and itsassociated components could be the stage. Also, what is described asstage 402 and its associated components could be the frame. The stagewould then include a coil that is wrapped around a core, and the framewould then support the longer coil that extends through the stage.

FIG. 5A illustrates a perspective view of a frame 500 and a stage 502that utilize yet another alternative embodiment of a transformer fornon-contact transfer of electrical power between frame 500 and stage502. FIG. 5B illustrates a top-plan view of frame 500 and stage 502 ofFIG. 5A. As with FIGS. 4A and 4B, note that only the portion of frame500 that is necessary to describe the use of the transformer isillustrated in FIGS. 5A and 5B. Frame 500 has a passageway 504 whereinthe inner surface of passageway 504 is lined with a primary coil 506.Stage 502 supports a secondary coil 508 that is rod-shaped. In otherwords, secondary coil 508 is a solenoid. Solenoid 508 passes throughpassageway 504. Note that the transformer does not utilize a core.However, in an alternative embodiment, an inductive core could beinserted down the center of solenoid 508.

Passageway 504 is sized larger than the diameter of solenoid 508 so thatsolenoid 508 can pass through passageway 504 without physical contact.In this way, stage 502 can move back and forth along the axis ofsolenoid 508 in a non-contact manner while power is supplied to stage502. Scanning axis 510 shows the direction in which stage 502 moves withrespect to frame 500.

The configuration of the transformer of FIGS. 5A and 5B can also beimplemented in an opposite fashion as shown. In other words, in analternative embodiment, what is described above as frame 500 and itsassociated components could be the stage. Also, what is described asstage 502 and its associated components could be the frame. The stagewould then include a passageway that is lined with an inductive coil,and the frame would then support the solenoid that passes through thepassageway of the stage.

Other non-contact techniques for transferring power between stage 200and frame 202 include the use of radio frequency transmission, radiationtransmission, and electrical arcing.

In addition to transferring power to stage 200, it is also useful tobuffer or store the transferred power within stage 200. Buffering refersto the temporary storage of a utility by the stage in order to enableefficient transfer of the utility or to make the utility more suited tospecific needs or limitations of various stage subsystems. Electricalpower can be buffered by various devices such as rechargeable batteries,capacitors, and ultra-capacitors. Of the three options, ultra-capacitorscan be charged faster than conventional rechargeable batteries and havemore capacity than conventional capacitors. Ultra-capacitors also havehigher specific power than conventional batteries and higher specificenergy than conventional capacitors. Ultra-capacitors also have slowerdegradation rates than conventional rechargeable batteries. Thesebuffering devices can be placed within electronics compartments 220 ofstage 200.

Another utility to transfer between stage 200 and frame 202 areelectrical signals. Electrical signals can carry the instructions anddata for the various processors installed within stage 200. Suchprocessors can control amplifiers, drivers, actuators, and sensors alsoinstalled within stage 200. Memory devices for storing electricalsignals can also be placed within stage 200. Electrical signals can betransmitted in various ranges of the electromagnetic spectrum but aretypically transmitted through radio frequency (RF) signals or throughoptical signals (e.g., infrared signals).

Radio frequency transceivers, transmitters, and receivers, which arerepresented by boxes 222, can be placed within electronics compartments220 of stage 200 and in various positions in or on frame 202. Thecommunication components 222 in each of stage 200 and frame 202 shouldbe positioned such that a clear communication channel between stage 200and frame 202 is maintained during the scanning motion of the stage.That is, the transceivers should be positioned such that radio frequencyinterference is avoided.

Optical signal transceivers, transmitters, and receivers, which arerepresented by boxes 224, can also be placed within electronicscompartments 220 and in various positions within or one frame 202.Optical signal transmission is advantageous because signals can betransmitted over high-bandwidth channels.

Optical communications components 224 can be placed such that theoptical signals travel between the optical components 224 on stage 200and frame 202 in a direction that is parallel to scanning axis 218. Inthis way, optical communication can be maintained throughout thescanning motion range of stage 200. For example, the optical component224 in stage 200 is placed in the electronics compartment 200 on theright-hand side, as seen in FIG. 3, and an optical component 224 isplaced at the far surface of frame 202, as seen in FIG. 2 such that theoptical components in stage 200 and frame 202 align with each other. Inalternative embodiments, optical components 224 can be placed such thatthe transmitted optical signals do not travel in a direction parallel toscanning axis 218. In such a configuration, direct communication betweenstage 200 and frame 202 is possible when stage 200 is stationary or onlywhen stage 200 and frame 202 come into correct relative positioning foroptical components 224 to match up during a scanning process.

During a lithography operation, heat is generated at stage 200 and needsto be removed for various reasons. One reason is that heat can causeslippage of contact between a stage or chuck and a reticle due todifferences in material thermal expansion coefficients. Heat transfertechniques can take advantage of convection, conduction, and/orradiation. Convection, which involves heat transfer in a gas or fluid bythe circulation of currents from one region to another, is effective innon-vacuum environments. Conduction, which involves heat transferthrough a gas in a gap too small to allow the generation of convectioncurrents is possible in low vacuum and is most effective in non-vacuumenvironments.

Heat can also be transferred through radiation, which involves theemission and propagation of energy in the form of rays or waves.Radiation heat transfer techniques are applicable in either vacuum ornon-vacuum environments.

Heat transfer surfaces 226 on each of stage 200 and frame 202 can takeadvantage of thermal conduction and/or radiation. Heat transfer surfaces226 on stage 200 can serve as heat sinks that collect heat from heatsources in stage 200. Heat is channeled to surfaces 226 that function asheat sinks by conduction through high specific conductive materials suchas graphite foam. Thermosyphons can also be used. As generally known,thermosyphons can be heat pipes depending on relative elevation ofevaporators and condensers and if there are acceleration forces, whichcan hinder return fluid flow. Thermosyphons are advantageous since theyare lightweight and have very high equivalent specific conductivity.This allows for a large amount of heat transfer in lightweightstructures over small temperature gradients. By maintaining the heattransfer surfaces 226 on frame 202 at a lower temperature than that ofthe heat transfer surfaces 226 on stage 200, heat collected at heattransfer surfaces 226 on stage 200 can be drawn into heat transfersurfaces 226 within frame 202. One or more heat transfer surfaces 200can be placed on stage 200 and frame 202 and they can have differentsizes and shapes depending upon the specific requirements of alithography system.

Heat transfer surfaces 226 can be on one or more surfaces of stage 200.For example, heat transfer surfaces 226 can be on the top, bottom,and/or the side surfaces of stage 200. Corresponding heat transfersurfaces 226 on frame 202 should match up to each other when stage 200is installed within frame 202.

Removing heat from stage 200 is more effective when the overalltemperature of frame 202 is maintained a temperature that is lower thanthat of stage 200. Various techniques can be used to maintain frame 202at a certain temperature. One technique for maintaining a lowtemperature of frame 202, which is represented in FIG. 2, uses coolingchannels 228 that run throughout the body of frame 202. Cooling channels228 allow coolant, e.g., water, to run remove heat from frame 202.

If the temperature of reticle stage 200 changes significantly, the stagematerials will expand and/or contract, which can distort reticle 200 andreticle chuck 207 and reduce stage performance. To avoid this problem,the stage structural material can be made of a low thermal expansionmaterial such as Zerodur™ (made by Schott Lithotec). This will makestage 200 less sensitive to internal temperature changes.

Some lithography systems require the exchange of gas and/or fluidsbetween a reticle and/or wafer stage for various purposes. Non-contacttechniques for transferring gas and fluids can utilize phase changeproperties of materials. Also fluids can be directly deposited onto astage from a frame.

One technique for transferring gas without involving physical contactbetween stage 200 and frame 202 involves an inverted cavity within theupper half of frame 202. FIG. 6 illustrates an enlarged, cross-sectionalview of stage 200 and frame 202 where non-contact transfer of gas andfluids can occur. The upper half of frame 202 includes an invertedcavity 250 on its bottom surface 252. Cavity 250 also has a supplypassageway 254 that leads to a reservoir or pressure vessel 256 and acollection passageway 258 that leads to another reservoir or pressurevessel 260. Valves 262 control the flow of gas or fluids throughpassageways 254 and 258. Stage 200 includes a well 264, a passageway 266that leads to a reservoir or pressure vessel 268, and a valve 262 thatcontrols the flow of gas or fluid through passageway 266. In someembodiments of the invention, a single passageway and reservoir that canboth expel and collect gases and fluids in frame 202 is sufficient. Inan alternative embodiment, the inverted cavity can be formed in a bottomsurface of stage 200 and a well can be formed in the top surface of thelower half of frame 202. In yet another embodiment, a inverted cavityand well combination is located in both the top and bottom surfaces ofstage 200.

One technique for transferring gas or fluid from stage 200 to frame 202involves releasing gas from reservoir 268 through passageway 266 suchthat it is captured by inverted cavity 250. Then collection passageway258 sucks the gas into reservoir 260. After the gas is collected, thegas can be cooled so that it changes into liquid form if needed. In theembodiment shown in FIG. 6, the diameter of inverted cavity 250 islarger than the diameter of well 264 such that the opening of invertedcavity 250 completely encompasses the opening of well 264. In someembodiments, the opening of inverted cavity 250 is large enough tocompletely encompass well 264 throughout the range of motion that stage200 travels during a scanning process. In such an embodiment, invertedcavity 250 is able to collect substantially all of the gas released byreservoir 268. Vacuum devices 270 can be positioned around the perimeterof inverted cavity 250 of frame 202 in order to evacuate any gases thatare not collected by inverted cavity 250. In alternative embodiments,vacuum devices can also be positioned on the top surface of stage 200 atpositions surrounding inverted cavity 250.

In alternative embodiments, stage 200 does not actually include well264. In such embodiments, gas is released at the top surface of stage200 directly through the opening of passageway 266. In turn, invertedcavity 250 can have a smaller diameter than that shown in FIG. 6,wherein the diameter of inverted cavity 250 is approximately the samesize or slightly larger than the diameter of passageway 266.

This technique of releasing gas from reservoir 268 is effective whenstage 200 and frame 202 operate in non-vacuum conditions. However, thistechnique can be used in vacuum conditions when a low-pressure gas istransferred.

A fluid can be transferred from stage 200 to frame 202 throughevaporation techniques. This involves releasing fluid from reservoir 268into well 264. Then a heating element heats the fluid in well 264 sothat it evaporates and is captured in inverted cavity 250. At thatpoint, collection passageway 258 can suck the gaseous form of the fluidinto reservoir 260. Again, gaseous form of the fluid can be convertedback to fluid form if desired. In one embodiment, the heat used toevaporate fluid in well 264 can come from the heat generated by thereticle stage or the wafer stage due to normal operating conditions.Such heat can be channeled towards well 264 through heat conductivematerials or heat pipes. Alternatively, well 264 can be placed adjacentto a heat sink in stage 200. In other embodiments, no heating isrequired to cause the fluid in well 264 to evaporate.

Fluid can be transferred from frame 202 to stage 200 using varioustechniques. One technique takes advantage of the condensation of gases.This involves maintaining the temperature of stage 200 or well 264 at atemperature that is sufficiently low such that a gaseous form of thefluid to be transferred condenses in well 264. To implement thistechnique, a gaseous form of the fluid is released from reservoir 256through passageway 254. Then the gas will condense on the surface ofwell 264, which is maintained at a sufficiently low temperature. Thecondensed fluid can then be collected through passageway 266 and intoreservoir 268. The bottom surface of well 264 is sloped downwards towardthe opening of passageway 266 to facilitate the collection of thecondense fluid.

Another technique for transferring fluid from frame 202 to stage 200involves pouring the fluid from passageway 254 of frame 202 into well264. It should be appreciated that various devices can be used to expeland collect gases and or liquids at each of inverted cavity 250 and well264. Also, the depth of inverted cavity 250 and well 264 can vary fromvery shallow to relatively deep.

Contact techniques for transferring utilities between a stage and aframe can also allow a lithography system to satisfy the positioningtolerances for the stage and to maintain a substantiallycontaminant-free processing environment. Contact utilities transferinvolves utilities transfer where there is more than zero stiffnessbetween the base and stage and the transfer devices apply asubstantially non-zero net force on the stage. To satisfy the tolerancesand cleanliness requirements of lithography systems, contact techniquesfor transferring utilities are performed when a stage is stationary withrespect to the supporting structure (the frame). For example, utilitiestransfer can occur with the reticle stage during wafer exchange andwafer alignment. When a reticle or wafer stage comes to a stationaryposition, physical connections between a transfer device on a frame aremade with a transfer device on the stage. Then after the transfer ofutilities is completed and the physical connections are disconnected,the stage can begin its scanning motions again. In some embodiments, thetransferred utilities are stored or buffered by the stage so that theycan be used during wafer scanning process.

FIG. 7 illustrates a side, cross-sectional view of a stage 300 and aframe 302 that transfers utilities through contact techniques accordingto one embodiment of the present invention. Reticle 312 is supported bystage 300.

Electrical power and electrical signals are transferred between a stageand a frame through electrical conductors. These conductors can take onvarious forms, such as cables, wires, or electrodes. The conductorsterminate with a terminator, for example a contact pad, so thatterminators on a stage can mate with a terminator on a frame. Theconductors can make contact with each other when the stage comes to astationary position with respect to a frame. For instance, conductors304 in stage 300 and frame 302 will come into contact with each otherwhen stage 300 become stationary and is lowered onto frame 302. Uponcontact, conductors 304 connect power source 314 within frame 302 andpower buffer device 312 within stage 300.

In an alternative embodiment, conductors 304 can make contact with eachother without lowering stage 300 onto frame 302 by having conductors 304extend out from either stage 300 or frame 302 or both. Such extendingconductors can be metal prongs, cables, or wires that are designed toextend from either stage 300 or frame 302.

The electrical power and electrical signals can be buffered using thesame techniques described earlier with respect to non-contact power andsignal transfer.

Heat transfer in contact transfer techniques can utilize mass, fluid,and gas exchange and conduction. In exchange techniques, a mass or anobject, fluid, and/or gas is transferred between stage 300 and frame 302when stage 300 is stationary.

Fluids and gases are transferred between a stage and a frame to be usedas a coolant to remove heat from stages. Fluids and gases are injectedinto cooling channels within stage 300. The fluid (or gas) then collectsheat as it is circulated around stage 300. When the fluid (or gas)collects a certain amount of heat, it is then removed from stage 300,and then replaced with another injection of low temperature fluid (orgas). The fluids or gases can also be utilized for fluid or gas filmsthat separate, for example, a reticle and the chuck that supports thereticle. The fluid or gas films facilitate heat transfer away from thereticle and into the chuck, stage, or heat sinks.

Fluid and gas coolants can be transferred through hoses 306 when stage300 is stationary. In essence, heat is transferred intermittently fromstage 300. This is implemented by connecting hoses 306 to stage 300 whenit is stationary, and then disconnecting the hoses before the stagebegins its scanning motions. Specifically, hoses 306 provide a path forgas or fluid to travel between a cooling system 308 within stage 300 anda reservoir 310 within frame 302. Hoses 306 can extend from frame 302 toconnect with stage 300, or hoses 306 can extend from stage 300 toconnect with frame 302. Various mechanical devices, such as actuatorscan be used to extend hoses 306.

An alternative to hoses for transferring fluids and gases are fixedports on each of stage 300 and frame 302. FIG. 8 illustrates an enlargedview of the interface between stage 300 and frame 302 according to analternative embodiment of the invention wherein ports 312 make contactwith each other in order to transfer gases and/or fluids. Ports 312 comeinto contact with each other when stage 300 is lowered onto the lowersupporting surface of frame 302. Stage 300 includes a reservoir orpressure vessel 314, a passageway 316 that leads from reservoir 314 toport 312. A vacuum pump 318 is connected to passageway 316 and hasvacuum pipes 320 that lead to the surface of stage 300 at points aroundthe perimeter of port 312. Valves 322 are used to control the flow offluids or gases through passageway 316 and vacuum pipe 320. Frame 302includes a reservoir or pressure vessel 330, a passageway 332 that leadsfrom reservoir 330 to port 312. A vacuum pump 334 is connected topassageway 332 and has vacuum pipes 336 that lead to the surface offrame 302 at points around the perimeter of port 312. Valves 338 areused to control the flow of fluids or gases through passageway 332 andvacuum pipe 336. Vacuum pump 318 can be used to evacuate any fluids orgases that escape from connecting ports 312 during a transfer process.

Gas exchange can be utilized in vacuum and non-vacuum processingenvironments. Helium or hydrogen can be used because of their high heatconductivity. Gases used as coolants should be maintained atlow-pressure levels to minimize their effect on the lithography systemin case they leak out from the hoses. Fluid exchange can be effectivelyused in non-vacuum environments. Water is an effective fluid coolant dueto its high specific thermal capacity.

Heat can also be exchanged between stage 300 and frame 302 through atechnique referred to as mass exchange. Mass exchange involves placing arelatively low temperature object within stage 300 to act as a heatsink. After the object collects a certain amount of heat, the object isremoved and then replaced with another relatively low temperatureobject. In this way, heat is transferred out of stage 300 along with theremoved object.

Heat can also be exchanged between stage 300 and frame 302 throughdirect contact between heat transfer surfaces on each of stage 300 andframe 302. Examples of heat transfer surfaces 226 can be seen in FIGS. 2and 3. Surfaces 226 can come into contact when the stage comes intocontact with the frame. A stage can have heat transfer surfaces on anyof its side, top, or bottom surfaces. In turn, the stage can be moved inany direction so that each of its surfaces that contain heat transfersurfaces can make contact with a mating heat transfer surface on theframe.

A type of material that can facilitate the removal of heat from stage300 is a phase change material (PCM), such as paraffin wax. PCM can comein a solid form that undergoes a phase change into a liquid form whensufficient heat is applied. PCM can store large amounts of energy aslatent heat during phase change from a solid to a liquid.Advantageously, in many applications, large quantities of thermal energycan be stored and released at a relatively constant temperature. This isso even when limited volumes and low operating temperature differencesare applicable.

PCM can come in a bound form wherein PCM is supported in a supportingstructure. Bound PCM is a composite material wherein PCM is suspendedthroughout a sponge-like or lattice type support structure. Each boundPCM can be in the size and form of a granule wherein a large quantity ofthe granules forms a powder that can be useful in heat transfertechniques. Bound PCM is advantageous in at least a couple aspects.First, even though PCM has a large capacity for storing heat, PCM is arelatively poor conductor of heat. Therefore, heat can be transferredmore easily to the PCM by spreading out PCM in a sponge-like supportstructure. Secondly, the sponge-like support structure retains the PCMafter it goes through its phase change into liquid form. Therefore,bound PCM avoids the difficulties of leaking PCM. An example of a boundPCM is Rubitherm™ PX.

One way to utilize PCM for heat transfer purposes is in mass transfer. Amass of PCM, for example a block, can be utilized as the mass that willcollect and store heat in a stage. The large amount of heat energy thatcan be stored by a mass of PCM increases the effectiveness of massexchange for heat transfer purposes.

Other ways to utilize PCM for heat transfer purposes uses PCM in thepowder form. PCM powder can be transferred to a stage in various contactmanners such that it can collect heat from a stage. For example, the PCMcan be transferred while suspended in a gas or liquid then transferredthrough hoses that connect a stage to a frame. The PCM increases theheat capacity of the transferred gas or fluid. Also, the PCM powderitself can be poured directly into and out

of the stage. For example, the PCM powder can be poured into the stagethrough an opening on a top surface of the stage. After the PCM powdercollects and stores a certain amount of heat, the PCM powder can then bedrained out of the stage. For example, a port on the bottom of the stagecan open so that the PCM powder drains out of the stage. Gravity can bethe force that causes the PCM to pour into and out of the stage. Funnelsand sloped surfaces within the stage can also be configured in so thatsuch openings can be created of side surfaces of a stage, in addition tothe top and bottom surfaces of a stage.

PCM can also be utilized to increase the heat capacity of a heat sinkpositioned within a stage. Such a heat sink is typically located betweenthe heat sources within a stage and the heat transfer surfaces on thesurface of a stage. A heat sink having suspended PCM within can be veryeffective. For example, PCM can be suspended within a graphite latticethat serves to spread out the PCM so that it can more easily collectheat energy. Alternatively, PCM can be spread out in thin layers withinthe heat sink. The thin layers of PCM can be positioned to runperpendicular to the heat flow axis. Again, the bound PCM allows thestage to store large amounts of thermal energy without significantlychanging the temperature of the stage.

As discussed above, the stage of the present invention can includevarious electronic and mechanical devices for handling variousprocessing, storing, or controlling functions. For example, on-boardelectronics within a stage can be provided for data processing, control,power conversion, energy storage, diagnostics, and reticle stagemonitoring. Such electronics include computer-processing units,actuators, piezo drives, sensor drives, electrostatic chuck drives,amplifiers, temperature sensors, gap sensors, and radio frequency andoptical transceivers. Drivers and amplifiers can be used for controllingthe sensors, actuators, and valves (for gas and fluid transfer). Driverscan also drive the actuators for moving the reticle with respect to thestage. Actuators types include but are not limited to fluid, ball-screw,electrostatic, and magnetic actuators. Controllers can controlfunctional aspects such as power consumption, signal processing, gas andfluid use. Computer processing units can be placed within a stage toprocess signals and monitor sensors on the stage. Sensors can be usedfor various measurements such as temperature, pressure, and distance.Typically, sensors are on placed on a frame, however the processing andbuffer devices on the stage allow sensors to be placed on the stage.Transformer can be used for AC/AC, AC/DC, and/or DC/DC power conversion.The various electronic and mechanical devices can be placed throughout astage or within electronics compartments within a stage. For example,FIG. 3 shows boxes 228, which represent various types of electrical andmechanical devices stored within electronics compartments 228.

Semiconductor devices can be fabricated using the above-describedsystems, by the process shown generally in FIG. 9. In step 1001 thedevice's function and performance characteristics are designed. Next, instep 1002, a mask (reticle) having a pattern it designed according tothe previous designing step, and in a parallel step 1003, a wafer ismade from a silicon material. The mask pattern designed in step 1002 isexposed onto the wafer from step 1003 in step 1004 by a photolithographysystem such as the systems described above. In step 1005 thesemiconductor device is assembled (including the dicing process, bondingprocess and packaging process), then finally the device is inspected instep 1006.

FIG. 10 illustrates a detailed flowchart example of the above-mentionedstep 1004 in the case of fabricating semiconductor devices. In step 1011(oxidation step), the wafer surface is oxidized. In step 1012 (CVDstep), an insulation film is formed on the wafer surface. In step 1013(electrode formation step), electrodes are formed on the wafer by vapordeposition. In step 1014 (ion implantation step), ions are implanted inthe wafer. The above mentioned steps 1011-1014 form the preprocessingsteps for wafers during wafer processing, and selection is made at eachstep according to processing requirements.

At each stage of wafer processing, when the above-mentionedpreprocessing steps have been completed, the following post-processingsteps are implemented. During post-processing, initially, in step 1015(photoresist formation step), photoresist is applied to a wafer. Next,in step 1016, (exposure step), the above-mentioned exposure device isused to transfer the circuit pattern of a mask (reticle) to a wafer.Then, in step 1017 (developing step), the exposed wafer is developed,and in step 1018 (etching step), parts other than residual photoresist(exposed material surface) are removed by etching. In step 1019(photoresist removal step), unnecessary photoresist remaining afteretching is removed. Multiple circuit patterns are formed by repetitionof these preprocessing and post-processing steps.

While this invention has been described in terms of several preferredembodiments, there are alteration, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. It is therefore intended that thefollowing appended claims be interpreted as including all suchalterations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

1. A lithography system comprising: a transformer that includes aninductive primary coil and an inductive secondary coil; a framesupporting the primary coil; and a stage device cooperating with theframe for relative movement therebetween substantially along apredetermined first direction, the stage device supporting the secondarycoil; said primary coil and said secondary coil substantially maintain aseparation distance from each other along a second direction thatintersects the predetermined first direction during said relativemovement between the stage device and the frame; wherein, an electricalcurrent within the primary coil creates an electromagnetic field thatcauses electrical current to flow within secondary coil.
 2. Alithography system as recited in claim 1, wherein the primary coil ispositioned proximate to the secondary coil.
 3. A lithography system asrecited in claim 1, wherein the stage device is supported over the framesuch that the stage device and frame remain physically separated fromeach other.
 4. A lithography system as recited in claim 1, wherein thesecondary coil is wound in the shape of an elongated loop.
 5. Alithography system as recited in claim 4, wherein the frame contains twopassageways and respective sections of the secondary coil passes througheach passageway.
 6. A lithography system as recited in claim 5, whereinthe frame includes an inductive core that separate each of the twopassageways and wherein the primary coil is wrapped around the inductivecore.
 7. A lithography system as recited in claim 1, wherein the framehas at least one passageway, and the secondary coil extends through thepassageway.
 8. A lithography system as recited in claim 1, furtherincluding: electrical components carried by the state device that drawelectrical current from the current created within the secondary coil 9.A lithography system as recited in claim 1, further comprising: at leastone of a stage radio frequency transmitter, a receiver, a transceiverand a battery that is supported by the stage device.
 10. A lithographysystem as recited in claim 1, wherein the stage device moves relative tothe frame substantially along a scanning axis.
 11. A lithography systemcomprising: a transformer that includes at least a primary inductivecoil and a secondary inductive coil, wherein the secondary inductivecoil has a first end and a second end, the first and second ends beingat opposite ends of a lengthwise axis of the secondary inductive coil; astage suitable for supporting a wafer or a reticle wherein the stage isattached to at least the first end of the secondary coil and therebysupports the secondary inductive coil; and a frame that supports theprimary coil such that the primary coil is proximate to the secondarycoil wherein the primary coil and the secondary coil maintain aseparation distance from each other when the stage moves relative to theframe along the lengthwise axis of the secondary coil, whereby anelectrical current within the primary coil creates an electromagneticfield that causes electrical current to flow within the secondaryinductive coil.
 12. A lithography system as recited in claim 11 whereinthe stage is supported over the frame such that the stage and frameremain physically separated from each other.
 13. A lithography system asrecited in claim 11 wherein the secondary coil is wound such that it hasthe shape of an elongated loop.
 14. A lithography system as recited inclaim 13 wherein the frame contains two passageways and respectivesections of the secondary coil passes through each passageway.
 15. Alithography system as recited in claim 14 wherein the frame includes aninductive core that separates each of the two passageways and whereinthe primary inductive coil is wrapped around the inductive core.
 16. Alithography system as recited in claim 11 wherein the frame has at leastone passageway, and wherein the secondary inductive coil extends throughthe passageway.
 17. A lithography system as recited in claim 11 whereinthe stage further comprises electrical components that draw electricalcurrent from the current created within the secondary inductive coil.